OBJECTIVE: The relationship between adverse childhood exposures and poor health, illness, and somatic complaints at age 12 was examined. METHODS: LONGSCAN (Consortium for Longitudinal Studies of Child Abuse and Neglect) tracks a group of children with variable risk for maltreatment. Of the participating child-caregiver dyads, 805 completed an interview when the child was age 4 or age 6, as well as interviews at age 8 and 12. The relationships between 8 categories of childhood adversity (psychological maltreatment, physical abuse, sexual abuse, child neglect, caregiver's substance/alcohol use, caregiver's depressive symptoms, caregiver's being treated violently, and criminal behavior in the household) and child health at age 12 were analyzed. The impact of adversity in the first 6 years of life and adversity in the second 6 years of life on child health were compared. RESULTS: Only 10% of the children had experienced no adversity, while more than 20% had experienced 5 or more types of childhood adversity. At age 12, 37% of the children sampled had some health complaint. Exposure to 5 or more adversities, particularly exposure in the second 6 years of life, was significantly associated with increased risks of any health complaint (odds ratio [OR] 2.24, 95% confidence interval [95% CI] 1.02-4.96), an illness requiring a doctor (OR 3.69, 95% CI 1.02-15.1), and caregivers' reports of child's somatic complaints (OR 3.37, 95% CI 1.14-1.0). There was no association between adverse exposures and self-rated poor health or self-rated somatic complaints. CONCLUSIONS: A comprehensive assessment of children's health should include a careful history of their past exposure to adverse conditions and maltreatment. Interventions aimed at reducing these exposures may result in better child health.